The invention is concerned with compositions which are useful for removing or stripping protective and/or decorative coatings from substrates. The invention is also concerned with a method for removing said coatings.
In the manufacture of various commercial articles, it is often the practice to provide such articles with a protective and/or decorative film of a coating composition, such as a paint film, on the surface of the article. Coating compositions, such as paints, are generally construed in their normal broad terms to include a variety of film forming compositions which are applied in a variety of manners, such as spraying and dipping, and include various means of application such as with or without organic carriers, water based substances, electrostatic sprays, application using various means of energy for curing, such as heat, electron beam, infrared, UV and the like. In general, the paint or coating composition is comprised of a variety of film forming materials, including acrylic resins, epoxy resins, vinyl resins, polyester resins as alkyd resins, urethanes and the like. In addition, the substrate to which the application of the coating composition is made generally has a corrosion protective coating applied thereto, such as an iron phosphate coating composition of the Bonderite type (trademark of Oxy Metal Industries Corporation).
In the course of manufacturing the articles, it becomes desirable to remove the protective coating for a number of reasons, such as an inappropriate or inadequate coating, some defect in the substrate and the like.
Use has been made in the past of chlorinated hydrocarbon paint stripping compositions. The difficulty with many of the previous paint stripping compositions are that they may take an inordinate amount of time or require components that are undesirable from the point of view of having a detrimental effect on the personnel who would be using the stripping compositions.
Canadian Pat. No. 708,141 teaches a paint stripping composition which contains a halogenated carboxylic acid, an organic sulfonic acid in an aqueous carrier.
U.S. Pat. No. 3,544,365 teaches the use of methylene chloride compositions containing triethanol amine lauryl sulfate, anionic oil suluble surfactant, plus formic acid as a composition for removing food residues.
U.S. Pat. No. 3,356,614 teaches a trichloroethylene composition containing an activator which is a combination of acetic acid and trichloroacetic acid for film stripping purposes.
The above and other compositions used in the trade are not sufficiently efficient in removal of the coating compositions from the substrate in a sufficient period of time.